he was here as a lawful resident. did he -- the thing i think that's the biggest question for investigators now is, "a," why did he turn this way? but, "b," where did he get his expertise in explosives? where did he practice them? it seems really unlikely these two bombs successfully were detonated without some practice runs. where did he learn to do that? where did he practice? those are the big questions. >> we look at the pictures of the suspects and biographical information we have, dzhokhar, who is the surviving suspect here, dzhokhar tsarnaev, is in hospital. tamerlan born in kyrgystan, comes in 2002. he becomes a u.s. citizen, 9/11/2012. he was a wrestler, enrolled at the university of massachusetts-dartmouth. so many friends talking so positively about him. tamerlan, his older brother, does that travel. he comes later than his younger brother. he was mayrried, had a 3-year-od daughter. had a domestic violence incident. he dropped out of community colle college. he was a competitive boxer. people speaking very